2. Field of the Invention
This invention relates to the production of edible filling materials for use in filled baked products such as pastries, crackers and cookies. More particularly, it relates to the production of filling materials which are thermostable and sheetable, so that they can be applied in layers to unbaked dough and then baked together with the dough.
2. Prior Art
Ready-to-eat baked goods containing filling materials such as cheese-flavored fillings, cremes and the like generally have exhibited short shelf lives. The short shelf lives of these products are caused primarily by the high water contents and high water activities of the filling materials. The water activity (A.sub.w) of a food is defined as the partial vapor pressure of water in the food divided by the saturation vapor pressure of pure water at the temperature of the food. It can be measured by placing a sample of the product to be tested in a container, which is then sealed, and determining the relative humidity above the sample after equilibrium is reached. Water activity can be considered to be a measure of the tendency of the material to allow water to migrate out of the material to its surrounding environment.
The relatively high water activities associated with prior art filling materials are problematical in several respects. When the filling material is in contact with a material of lower water activity, such as a baked dough, moisture tends to migrate from the filling material into the baked dough, making the baked dough portion soggy. Moreover, filling materials having high water activities provide a medium which is conducive to microbial growth.
For the foregoing reasons, it would be desirable to produce filling materials having relatively low water activities. In the past, filling materials having relatively low water activities have been produced by the addition of various humectants to the filling material formulations. The materials produced in this manner, however, have generally not been thermostable. Consequently, they could not be applied to a dough product prior to baking.